It has long been recognized that allowing consumers to design their own residential solar system would be desirable. For solar installers, lead generation and sales have become a dominant cost, while for consumers the process of dealing with sales people and getting multiple quotes is painful and time-consuming. Both buyer and seller would benefit from technology that would allow a consumer to design their own solar system since it could allow consumers to automatically generate a bid, all but eliminating sales costs and effort.
If the size and shape of a roof, its azimuth and inclination angles, and obstructions that shade the roof are known, solar system design is straightforward, and could potentially be automated. Professional solar installers collect this information by going on the roof and taking measurements and using instruments to determine shading. It is obviously impractical to expect a consumer to measure their roof and to have available the special instrument that measures shading.